U.S. patent application number 10/637124 was filed with the patent office on 2005-02-10 for incoming message decoding in wireless communications devices and methods.
Invention is credited to Abdesselem, Ouelid, Binzel, Charles, Boyer-Noel, Benoit, Kaluzny, Mark, Menu, Estelle, Radakovic, Daniela.
Application Number | 20050030914 10/637124 |
Document ID | / |
Family ID | 30470332 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050030914 |
Kind Code |
A1 |
Binzel, Charles ; et
al. |
February 10, 2005 |
Incoming message decoding in wireless communications devices and
methods
Abstract
A method in a mobile wireless communication device capable of
receiving a paging message transmitted in a series of bursts over
successive time frames including receiving (210) not more than one
burst of an incoming paging message, determining (220) whether the
incoming paging message corresponds to a known paging message, and
(230) reducing power consumption of radio circuits of the mobile
wireless communication device during time frames when other bursts
would be received if the incoming paging message corresponds to the
known paging message. If the incoming data does not correspond to
the known data, additional burst are received and decoded.
Inventors: |
Binzel, Charles; (Bristol,
WI) ; Abdesselem, Ouelid; (Toulouse, FR) ;
Boyer-Noel, Benoit; (Grisolles, FR) ; Kaluzny,
Mark; (Grayslake, IL) ; Menu, Estelle;
(Ramonville St Agne, FR) ; Radakovic, Daniela;
(Park Ridge, IL) |
Correspondence
Address: |
MOTOROLA INC
600 NORTH US HIGHWAY 45
ROOM AS437
LIBERTYVILLE
IL
60048-5343
US
|
Family ID: |
30470332 |
Appl. No.: |
10/637124 |
Filed: |
August 8, 2003 |
Current U.S.
Class: |
370/312 ;
370/321 |
Current CPC
Class: |
H04W 52/0216 20130101;
H04W 52/0229 20130101; H04W 68/00 20130101; H04L 1/0045
20130101 |
Class at
Publication: |
370/312 ;
370/321 |
International
Class: |
H04H 001/00; H04B
007/212 |
Claims
What is claimed is:
1. A mobile wireless communication device capable of receiving a
paging message transmitted in a series of bursts over successive
time frames, comprising: receiving not more than one burst in a
corresponding time frame of an incoming paging message; determining
whether the incoming paging message corresponds to a known paging
message based on the not more than the one burst received; reducing
power consumption of radio circuits of the mobile wireless
communication device during time frames when other bursts would be
received if the incoming paging message corresponds to the known
paging message.
2. The method of claim 1, comparing incoming data of the not more
than one burst with known data of a corresponding burst of a known
paging message, combining the incoming data with known data of a
burst in a different time frame of the known paging message only if
results of comparing satisfy a specified requirement.
3. The method of claim 2, reconstructing the incoming paging
message by decoding the combined incoming data and the known data,
determining whether the reconstructed incoming paging message
corresponds to the known paging message.
4. The method of claim 3, receiving the known paging message in
several bursts over successive time frames, storing the known data
from at least a portion of the known paging message.
5. The method of claim 2, measuring a channel quality of the
incoming paging message, resealing the known data based on the
channel quality of the incoming paging message.
6. The method of claim 1, comparing incoming data of the not more
than one burst with known data of a corresponding burst of a known
paging message, receiving another burst in a successive time frame
of the incoming paging message if the results of comparing do not
satisfy a specified requirement, reconstructing the incoming paging
message by decoding the data from the bursts received.
7. The method of claim 6, assuming that data from bursts of the
incoming message not received is unreliable before reconstructing,
determining whether the reconstructed incoming paging message
corresponds to the known paging message.
8. The method of claim 1, receiving the not more than one burst of
the incoming paging message by receiving a burst in a first time
frame of the series of consecutive time frames, comparing incoming
data of the burst of the first time frame of the incoming paging
message with known data of a burst of a first time frame of the
known paging message, combining the incoming data of the burst of
the first time frame of the incoming paging message with known data
of bursts of other time frames of the known paging message only if
results of comparing satisfy a specified requirement,
reconstructing the incoming paging message by decoding the combined
incoming data and the known data, determining whether the incoming
paging message corresponds to the known paging message.
9. The method of claim 1, receiving the not more than one burst of
the incoming paging message by receiving a burst in a second time
frame of the series of consecutive time frames, comparing incoming
data of the burst of the second time frame of the incoming paging
message with known data of a burst of a second time frame of the
known paging message, combining the incoming data of the burst of
the second time frame of the incoming paging message with known
data of a burst of different time frames of the known paging
message only if results of comparing satisfy a specified
requirement, reconstructing the incoming paging message by decoding
the combined incoming data and the known data, determining whether
the incoming paging message corresponds to the known paging
message.
10. A mobile wireless communication device capable of receiving an
incoming message transmitted in a series of portions over
consecutive intervals, comprising: receiving a portion of an
incoming message of not more than a single one of the consecutive
intervals; combining the portion of the incoming message with a
portion of a known message; reconstructing a message from the
portion of the incoming message and the portion of the known
message.
11. The method of claim 10, operating a radio circuit of the mobile
wireless communication device in a reduced power consumption mode
during remaining intervals of the incoming message if the incoming
message corresponds to the known message.
12. The method of claim 10, receiving a no-identity paging message
transmitted in several bursts over consecutive time intervals;
storing known paging data from at least a portion of the
no-identity paging message, the known paging data corresponding to
the known message.
13. The method of claim 10, receiving the portion of the incoming
message in not more than a first one of the consecutive
intervals.
14. The method of claim 10, receiving the portion of the incoming
message in not more than a second one of the consecutive intervals
without receiving any portion of the incoming message in a first of
the consecutive intervals.
15. The method of claim 14, receiving another portion of the
incoming message in a third one of the consecutive intervals if the
incoming message doe not correspond to the known message.
16. The method of claim 10, comparing the portion of the incoming
message with a corresponding portion of a known message; combining
the portion of the incoming message with the portion of the known
message only if results of comparing the portion of the incoming
message with the corresponding portion of the known message satisfy
a specified requirement.
17. The method of claim 10, resealing the portion of the known
message based on a channel quality of the incoming message.
18. The method of claim 10, combining the portion of the incoming
message with the portion of the known message by combining the
portion of the incoming message of not more than one consecutive
interval with portions of the known message from all other
intervals of the incoming message not received.
19. A mobile wireless communication device capable of receiving an
incoming message transmitted in a series of portions over
successive intervals, comprising: receiving portions of an incoming
message in at least two successive intervals without receiving a
portion of the incoming message in a first of the successive
intervals; decoding the portions of the incoming message
received.
20. The method of claim 19, the incoming message transmitted in a
series of burst over consecutive time frames, receiving bursts of
at least second and third consecutive time frames, decoding data of
the burst of the second and third consecutive time frames.
21. The method of claim 19, the incoming message transmitted in a
series of burst over consecutive time frames, receiving bursts of
at least third and fourth consecutive time frames, decoding data of
the burst of the third and fourth consecutive time frames.
22. The method of claim 19, determining whether the decoded message
is valid.
23. The method of claim 19, receiving an additional portion of the
incoming message in a successive interval if the decoded message is
invalid.
Description
FIELD OF THE INVENTIONS
[0001] The present inventions relate generally to wireless
communications, and more particularly to incoming message decoding
in wireless communications devices capable of receiving information
transmitted in portions over successive intervals, for example
cellular communications handsets that receive messages transmitted
in a series of bursts over consecutive TDMA time frames, methods
and apparatuses therefor.
BACKGROUND OF THE INVENTIONS
[0002] The Groupe Special Mobile (GSM) communication protocol
includes two general classes of communications channels, dedicated
channels and broadcast channels. The common channels are based on a
51 TDMA frame cycle including multiple Common Control Channel
(CCCH) frames, Frequency Control Channel (FCCH) frames, and
Synchronization Channel (SCH) frames. The CCCH may be an Access
Grant Channel (AGCH) or a Paging Channel (PCH). Channel information
is transmitted during multiple time-slots in consecutive frames.
For example, every CCCH data block is transmitted in a series of
four data bursts in corresponding time-slots of consecutive CCCH
time frames.
[0003] It is known to conserve power in wireless communications
devices operating in idle mode when not communicating by
configuring radio circuits and digital signal processor (DSP) in a
sleep mode. The microprocessor control unit (MCU) wakes-up the
radio circuits and DSP from the sleep mode with a command when it
is time to receive the incoming data bursts, which are transferred
to the DSP from the radio circuits. The radio circuits and DSP must
remain awake to receive all data bursts in the data block, for
example during the 1.sup.st, 2.sup.nd, 3.sup.rd and 4.sup.th time
frames of a CCCH message. A command from the MCU on the final burst
instructs the DSP to decode the PCH burst data. After the DSP
decodes the burst data received, the DSP sends the decoded data to
the MCU.
[0004] U.S. Pat. No. 5,570,369 entitled "Reduction of Power
Consumption In A Mobile Station" discloses attempting to recover
data bits of a four-burst message by de-interleaving data from at
least the 1.sup.st and 2.sup.nd bursts while assuming that data
from the remaining bursts of the message are unreliable. The
de-interleaved data bits are de-convoluted with a Modified
Selective-Repeat Type-II Hybrid ARQ based de-convolution algorithm,
and the result is FIRE decoded in an effort to reconstruct the
original information. If reconstruction is unsuccessful, then the
3.sup.rd data burst is received and the de-interleaved data bits
thereof are combined with the de-interleaved 1.sup.st and 2.sup.nd
data bits, and the combined data bits are de-convoluted with a
Viterbi algorithm before FIRE decoding. Power consumption of the
device is reduced by operating radio circuits of the mobile station
in sleep mode during the time frames when the 3.sup.rd and/or
4.sup.th bursts are transmitted if the original information may be
reconstructed with only two or three data bursts. The methods of
U.S. Pat. No. 5,570,369 require receiving at least the 1.sup.st and
2.sup.nd bursts of the four-burst PCH or BCCH message
transmitted.
[0005] The various aspects, features and advantages of the present
invention will become more fully apparent to those having ordinary
skill in the art upon careful consideration of the following
Detailed Description of the Invention with the accompanying
drawings described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is an exemplary mobile wireless communications
device.
[0007] FIG. 2 is an exemplary process flow diagram for one aspect
of the invention.
[0008] FIG. 3 is a more detailed burst data reception and decoding
process flow diagram related to the process diagram of FIG. 2.
[0009] FIG. 4 illustrates combining incoming burst data from not
more than one time frame with known burst data from other time
frames where there is a likelihood that the incoming message
corresponds to a known message.
[0010] FIG. 5 is an exemplary process flow diagram for another
aspect of the invention where there is a not a likelihood that the
incoming message corresponds to a known message.
[0011] FIG. 6 illustrates a multi-frame message having data in the
1.sup.st and 2.sup.nd frames and unreliable data in the 3.sup.rd
and 4.sup.th frames.
DETAILED DESCRIPTION OF THE INVENTIONS
[0012] FIG. 1 is a mobile wireless communications device 100
capable of receiving incoming messages transmitted in a series of
portions over successive intervals, for example a wireless GSM
cellular communications handset capable of receiving incoming
messages transmitted in a series of bursts over consecutive TDMA
timeframes. The invention is applicable more generally to any
receiver that receives information in portions in successive time
intervals.
[0013] The device 100 comprises generally a transceiver 110 coupled
to a processor 120, which includes micro-controller and in some
preferred embodiments a digital signal processor (DSP). Memory 130,
for example a ROM, RAM and in some embodiments a PROM, is coupled
to the processor. The exemplary device 100 also includes a visual
display device 140, for example an LCD display, coupled to the
processor. The device also includes input devices 150, like a
microphone, keypad and other inputs, and output devices 160,
including a loudspeaker, audio output connectors, etc.
[0014] In FIG. 2, at block 210, the mobile wireless communication
device receives not more than one portion of information, for
example burst data, in a corresponding interval or time-slot of one
of a series of frames of an incoming message. At block 220, a
determination is made whether the incoming message corresponds to a
known message based on the not more than the one portion of the
message received.
[0015] In one embodiment, the message is a paging message. In the
GSM communications networks, for example, the device 100 receives
Paging Channel (PCH) information transmitted in a series of four
bursts in corresponding time-slots of consecutive CCCH frames. The
PCH is a control channel used for paging a mobile station (MS) when
there is an incoming call addressed to the MS. Every message on the
PCH channel addressed to an MS contains the paged MS identity
number, or the International Mobile Subscriber Identity (IMSI), or
Temporary Mobile Subscriber Identity (TIMSI). In the case where no
MS is being paged, a "No Identity Page" or like message is sent on
the PCH channel. At the mobile device, the decoded PCH burst data
may indicate that the MS is being paged, or that another MS is
being paged, or that no MS is being paged. Thus in some instances,
the paging message is addressed to the MS, or a paging message not
addressed to any device, also referred to herein as a "No Identity
Page". In other applications or embodiments, however, the message
may be some message other than a paging message, and thus this
aspect of the invention is not limited to paging messages.
[0016] In FIG. 2, at block 230, if the incoming message corresponds
to the known message, radio circuit power consumption of the mobile
wireless communication device is reduced during the time intervals
when other bursts of the incoming message are transmitted and would
be otherwise received. Under these circumstances, the device is
able to conserve power since it is not necessary to receive the
remaining bursts of the incoming message, since the incoming
message has been decoded correctly from only a portion of the
message transmitted.
[0017] FIG. 3 is a more detailed burst data reception and decoding
process flow diagram according to an exemplary embodiment of the
invention. At block 310, a single burst is received for a first
time frame. At block 320, after demodulation, incoming data bit
detection occurs at block 320 in a channel equalizer. During
equalization, the transmitted bit sequence is reproduced from the
demodulated burst.
[0018] After equalization, the incoming data is compared with known
data of a corresponding burst. For example, incoming data from the
1.sup.st time frame of the incoming message is compared with known
data from the 1.sup.st time frame of a known message. In FIG. 3, at
block 330, comparison of the known data and the incoming data is
performed by computing the differences between the corresponding
data bits of the incoming and known data, after equalization.
[0019] The known data used for the comparison may be obtained from
a database stored on the device, for example data from a previously
received message. The known data may be data from all bursts of the
known message, or it may be partial data from only a portion of the
bursts of the known message. The partial or complete data from the
known message is stored after equalization.
[0020] If results of the comparison at block 330 satisfy a
specified requirement indicating that there is a likelihood that
the incoming message corresponds to the known message, the data
from the received burst of the incoming message is combined with
known data from other bursts of the known message and decoded as
discussed further below. The extent of the correlation required
between the incoming data and the known data at the comparison
stage is based on empirical data and is dependent generally upon
the quality of the channel and possibly other factors or
conditions. The specified requirement may be judged relative to a
difference threshold or a ratio or some other measure, which may be
a function of channel quality, bit error rate, and a confidence
factor, among other factors.
[0021] In FIG. 3, at block 340, if the specified requirement is
satisfied, indicating the likelihood of a match, known data from
the known message is combined at block 350 with the incoming data
before deinterleaving at block 360. In one embodiment, the known
data is rescaled based upon the channel conditions during which the
incoming burst was received. In one embodiment, the resealing is
based upon the signal-to-noise ratio of the channel. The resealing
of the known data occurs prior to the combining of the known data
with the incoming data.
[0022] FIG. 4 illustrates the combination of incoming data received
from a burst in the 1.sup.st time frame 412 of a four-burst message
410 with known stored data from bursts in the 2.sup.nd through the
4.sup.th time frames 424, 426 and 428 of a known four-burst message
420, thereby producing a combined data message 430. The combination
of the incoming and known data occurs preferably after equalization
and before deinterleaving. As noted, the known data may be rescaled
based on present channel conditions prior to combining. In FIG. 4,
the 2.sup.nd through the 4.sup.th time frames of the incoming data
is illustrated in broken lines to indicate that the corresponding
incoming bursts have not been received yet for these frames.
[0023] In another embodiment, the incoming data received is that of
the 2.sup.nd time frame 414 instead of the 1.sup.st time frame 412.
In this alternative embodiment, the incoming data 414 of the
2.sup.nd time frame is combined with known data from the 1.sup.st,
3.sup.rd and 4.sup.th time frames of the known message. According
to this embodiment, the radio circuits may be operated in reduced
power consumption mode during the 1.sup.st time frame. The
reception of an incoming burst of the 2.sup.nd time frame without
receiving bursts of the 1.sup.st time frame is preferably performed
only when the channel quality is sufficiently good to ensure valid
decoding of the incoming message with the incoming data of not more
than the 2.sup.nd through the 4.sup.th time frames in the event
that the incoming message does not correspond to the known message,
or in the event that the incoming message cannot be decoded validly
with the data from only the 2.sup.nd time frame.
[0024] In another alternative embodiment, incoming data from the
3.sup.rd time frame 416 may be combined with known data from the
1.sup.st, 2.sup.nd and 4.sup.th time frames, thus permitting
reducing power consumption during the 1.sup.st and 2.sup.nd time
frames 412 and 414. The reception of incoming bursts of the
3.sup.rd time frame without receiving bursts of the 1.sup.st and
2.sup.nd time frames is preferably performed only when the channel
quality is sufficiently good to ensure valid decoding of the
incoming message with the incoming data of not more than the
2.sup.nd through the 4.sup.th time frames in the event that the
incoming message does not correspond to the known message, or in
the event that the incoming message cannot be decoded validly with
the data from only the 3.sup.rd time frame.
[0025] In FIG. 3, after combining at block 350, the combined data
is deinterleaved at block 360 and decoded at block 370. The
deinterleaving and decoding processes are known generally in the
art. Decoding generally includes a de-convolution step, for example
Viterbi decoding, and a subsequent validation operation, for
example FIRE decoding having a cyclic redundancy check (CRC)
algorithm, which performs limited error correction and indicates
whether the message has been reconstructed correctly. The
reconstructed message is returned to the processor or MCU at block
380.
[0026] During many time periods there are a substantial number of
"No Identity Page" messages transmitted by the communication
network, and thus substantial power savings may be attained by
early detection of No Identity Page messages, without receiving all
of four bursts.
[0027] In some embodiments, where MS processing capacity permits,
the incoming data portion from may be compared in parallel with
corresponding portions of more than one known message, for example
a "No Identity Page" and a page addressed to the MS, among other
known messages.
[0028] If the decoded message is invalid or unreliable, additional
bursts may be received and the incoming data therefrom may be used
to reconstruct the incoming message. In FIG. 3, if the comparison
results do not satisfy the specified requirement at block 340, the
burst of a successive time frame is received and data from the two
time frames is decoded.
[0029] In FIG. 5, at block 510, a 2.sup.nd burst is received, and
at block 520 incoming data from the 2.sup.nd burst is recovered by
the equalizer and subject to the deinterleaving operation.
Thereafter, incoming data from the 1.sup.st and 2.sup.nd time
frames is decoded. The data for the remaining time frames not yet
received, e.g., the 3.sup.rd and 4.sup.th time frames, is marked as
unreliable prior to decoding. FIG. 6 illustrates a four-frame
message 600 having data bits in the first and second frames 610 and
620, but no data bits in frames 630 and 640, which are designated
as having unreliable bits prior to deinterleaving and decoding.
[0030] In FIG. 5, at block 530, if decoding is successful, as
determined for example by FIRE decoding, the results are sent to
the processor at block 540. The radio circuits are also preferably
operated in reduced power consumption mode during the time frames
during which any remaining data portions, or bursts, are
transmitted, since it is unnecessary to receive this data.
[0031] If the decoding is unsuccessful at block 530, another burst
in the next successive time interval is received at block 550 and
the process repeats until decoding is successful or until the data
portions, or bursts, in all intervals, or time frames, are
received. The data for any timeslots not yet received is marked as
unreliable prior to decoding as discussed above.
[0032] In one embodiment, the radio circuits are operated in
reduced power consumption mode during the 1.sup.st interval or time
period of the data transmission, and the 1.sup.st burst received is
in the 2.sup.nd time frame. In this alternative embodiment, after
an unsuccesful comparison with any known data as discussed above,
the 2.sup.nd burst received at block 510 is in the 3.sup.rd time
frame, and any subsequent burst received is in the 4.sup.th time
frame, which is the last time frame for CCCH frames in GSM
networks. According to this embodiment, the radio circuit will
operate at most for three of the exemplary four time frames, and in
some instances the radio circuits may operate for only two of the
four time frames, i.e. the 2.sup.nd and 3.sup.rd time frames, if
decoding is successful for incoming data from only two received
bursts. This mode of operation will be reliable only where and when
channel conditions are optimum, but will provide substantial power
savings.
[0033] In another alternative embodiment, the 1.sup.st burst
received is in the 3.sup.rd time frame, and any subsequent 2.sup.nd
burst received, at block 510 in FIG. 5, is in the 3.sup.rd time
frame. The radio circuits are operated in reduced power consumption
mode during the 1.sup.st and 2.sup.nd intervals or time periods of
the data transmission. According to this embodiment, the radio
circuit will operate at most for two of the exemplary four time
frames, i.e., the 3.sup.rd and 4.sup.th time frames, if decoding is
successful for incoming data from only two received bursts. If
decoding is unsuccessful, the MS must wait for the next message
transmission. This mode of operation will only be viable where
channel conditions are optimum, but will provide substantial power
savings.
[0034] In embodiments where incoming data from only 2 time frames
are decoded, a decoding algorithm based on the publication authored
by S. Lin Wang entitled "A modified Selective-Repeat Type-II Hybrid
ARQ System and Its Performance Analysis", IEEE Transactions on
Communications, disclosed for example in of U.S. Pat. No. 5,570,369
entitled "Reduction of Power Consumption In A Mobile Station" may
be more efficient than a Viterbi decoding algorithm.
[0035] The equalization and decoding operations are performed in
the DSP as is known by those having ordinary skill in the art. The
comparison and weighting processes are also performed by the DSP.
In receivers having GSM architectures, a secondary control portion
resides inside the GSM signaling stack MCU code layer 1.
[0036] The present inventions thus provide methods for
significantly reducing power consumption in radio receivers by
operating in reduced power consumption mode when it is unnecessary
to receive burst data. The processing of received data portions is
streamlined by determining first whether the likelihood that an
initial incoming data portion corresponds to a known data portion,
and where the likelihood is good reconstructing and validating the
message by combining the received data portion with other known
data portions of the known message. If the likelihood is not good,
additional data portions are received and the message is decoded
with the assumption that any data portions not yet received are
invalid. The process repeats until decoding is successful, which
may be verified by a CRC operation. The inventions are applicable
to any communications system that receives message in portion
transmitted over successive interval, for example GSM
communications.
[0037] While the present inventions and what is considered
presently to be the best modes thereof have been described in a
manner that establishes possession thereof by the inventors and
that enables those of ordinary skill in the art to make and use the
inventions, it will be understood and appreciated that there are
many equivalents to the exemplary embodiments disclosed herein and
that myriad modifications and variations may be made thereto
without departing from the scope and spirit of the inventions,
which are to be limited not by the exemplary embodiments but by the
appended claims.
* * * * *